Let me preface this answer by applauding all of the excellent answers in here! :) They cover the most important aspects, usual suspects if you may.
I'll go ahead and split the aforementioned modes of communication into two main categories.
All formal communication, across both the verbal, and written channels — experientially speaking — fall into the above two buckets; either you are:
Often, it's a mix of both!
Sandeep's answer, and Milica's answer go into details on these modes of communication, and how/what they screen on these respective aspects.
Understanding this distinction, and improving on the corresponding characteristics, is what I would characterise as — working towards "good communication skills"!
One of the tools that I want to leave here for an aspirant on their way to becoming better at their skill of communication (especially communication during interviews), is The S.T.A.R. Method.
Hope this is of help! :-)